Wire tensioning tool

ABSTRACT

A fence wire tensioning tool includes an arm  2  with fixed jaws  7  attached to both sides and a positioning foot  4  which pivots about a bolt  8.  At the opposite end of the arm is fixed a movable jaw assembly  1,  which extends to form a handle  3.  This assembly rotates about a pivot pin  5,  which is secured by a hexagonal socket set screw  10.  The handle  3  may include a rubber or plastic hand grip  12  which affords a better purchase on the tool by the operator.

BACKGROUND OF THE INVENTION

This invention relates to a hand operated fence wire tensioning toolwhich can be used with all types of fence wire and in association with avariety of different size and types of fence post.

SUMMARY OF THE INVENTION

A number of different fence wire tensioning devices exist but theseusually rely upon a separate linkage to a straining post or second fixedanchor point, whilst operating with serrated jaws to achieve a grippingeffect. Such devices are often heavy, cumbersome in operation, timeconsuming to set up and use—and they invariably damage the plasticcoating or metal plating that is applied to the fence wire to preventrusting and deterioration.

A wire tensioning device is disclosed in GB-A-2185080 comprising a headfor engaging a post to which wire is to be attached and an elongatelever member. The head is pivotally connected to the lever member. Thehead and lever member having surfaces which define a reducible area forreceiving the wire. The lever is lent on to trap the wire in thereducible area and to tension the wire about the post.

A problem encountered with such prior art tools is that the head isformed with a curved and pointed surface for engaging a post. As thewire is stretched the head either slides round the post or, the headpivots on a progressively smaller point of contact. Thus as the tensionin the wire increases the tool becomes progressively more unstable asthe head moves away from the post.

An object of this invention is to provide a simple and effective meansof tensioning fence wires before stapling in the usual way—especiallywhen an operative is working alone and without mechanical aids such as atractor, ratchet device or pulley system; or more particularly whenworking in a restricted, sloping or uneven working position where suchdevices may be difficult or unsafe to operate. It is a further object toovercome the aforementioned problem with the prior art.

Accordingly the invention provides a fence wire tensioning toolcomprising a pivoting foot for engaging a fence post, a handle memberincluding a first jaw surface, the handle member being pivotallyattached to an intermediate arm member carrying a second jaw surfaceopposing said first jaw surface to provide jaws for gripping a fencewire, the pivoting foot member being pivotally attached to saidintermediate arm member, whereby when the jaws are closed on a wire theintermediate arm member and the handle provide a lever pivoting aboutthe pivot point of the pivoting foot. The foot bearing on a fence postprovides a constant bearing surface so that the stability of the tool isimproved as the amount of tension applied to the wire increases.

The pivoting foot may have an arcuate bearing surface. The bearingsurface may be serrated, ribbed, denticulate or covered with a frictiontype material. The gripping section may be made of Durbar (RTM) orsimilar sheet or plate material which offers a pre-formed surfacetexture. The radius of the bearing surface is dependent on the size offence post on which it is intended to be used. The bearing surfaceradius may be in the range 40 to 100, preferably 60 to 80 mm. Thebearing surface radius may be 75 mm.

The leverage applied to the handle effects a class 2 lever actingagainst the pivot point of the positioning foot. Simultaneously, adouble class 1 lever action is effected on the wire held between thejaws. The arrangement allows a single handed action.

The wire is gripped by said jaws, which may engage by means of aneccentric cam action. This arrangement reduces the damage to the surfaceof the wire as the force on the wire is distributed evenly across thejaws to reduce the risk of the wire being cut or distorted by pointcontact and preventing slippage.

Each of said intermediate arm member and said handle may include pairsof said first and second opposing jaw surfaces. The jaws on both sidesof the tool allow both left handed and right handed operation of thetool.

The wire tensioning tool may comprise a resilient means associated withthe handle and acting against the leverage applied to the handle. Theresilient means may conveniently be a compression spring. It has beenfound that the presence of the resilient means assists in opening thejaws once a wire has been put in place.

The handle may be provided with a rubber or plastic friction handgrip.The handle may be attached to a jaw assembly by swaging. Alternativelythe handle is attached by means of welding, brazing, a screw thread,rivets, socket or force fit to. spigot.

The wire tensioning tool may be made from metal, plastics material,rubber, or from a combination of these and other suitable materials.Preferably the fence wire tensioning tool is made out of metal butcertain parts of it may instead be constructed from modem materials suchas carbon fibre or certain plastics, which offer advantages for ease ofmanufacture or weight reduction without compromising the necessaryleverage required to operate successfully.

A fence wire tensioning tool including a handle and fixed and movablejaws and a pivoting foot or other similar device which can be positionedagainst or effect a means to engage a fence post for the purpose oftensioning fence wires prior to stapling in the usual way is provided.

The tool of the invention may be advantageously used for all purposeswhere it is desired to tension wires and may be particularly useful inthe agricultural, horticultural and construction industries. The toolmay also be sold via the DIY trade.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, and by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 shows a plan view of the fence post and wire, with the tool inposition before a wire is tensioned.

FIG. 2 shows a plan view of the tool and a fence post with the wire intension after leverage has been applied to the handle and jaws haveengaged the fence wire.

FIG. 3 shows a front elevation of the tool and a fence post with thewire shown engaged between the jaws.

FIG. 4 shows a partial view of a movable jaw assembly in section andindicates the position of a return compression spring and movementlimiting pin.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the fence wire tensioning tool comprises an arm 2with fixed jaw surfaces 7 attached to both sides. The fixed jaw surfaces7 are arranged at an angle to the axis of the arm 2. In this embodiment,the jaw surfaces are at an angle of 20° to the normal of thelongitudinal axis of the arm 2. The fixed jaw surfaces 7 may havesurfaces that are rounded at least at the leading edge. Also attached tothe arm 2 is a positioning foot 4. The positioning foot 4 is secured tothe arm by a bolt 8 and a self-locking nut 9. The positioning foot 4 islocated proximate one end of the arm 2 and pivots about the bolt 8. Thepositioning foot 4 has an arcuate bearing surface 4 a. The radius of thebearing surface 4 a is about 75 mm.

At the opposite end of the arm 2 is a movable jaw assembly 1 whichextends to form a handle 3 to which is attached a rubber or plasticfriction handgrip 12. The assembly 1 pivots about a pin 5, which issecured to the arm 2 by a hexagonal socket set screw 10. The jawassembly 1 has a pair of arcuate jaw surfaces 1 a opposing the pair offixed jaw surfaces 7.

As shown in FIGS. 2 and 3, the pivot pin 5 allows the movable jawassembly 1 to turn about the arm 2, so engaging the fence wire 13 withthe fixed jaw surface 7 by means of an eccentric cam action. Theeccentric cam action is achieved by positioning the pin 5 offset fromthe centre of curvature of the jaw surfaces 1 a.

As shown in FIG. 4, a compression spring 11 is retained within a blindhole of the movable jaw assembly 1. The spring 11 opposes the rotationalmovement of the fixed jaw surface 7 and movable jaw assembly 1 andassists in releasing the grip on the fence wire when pressure on thehandle 3 is removed. A movement limiting pin 6 engages in a taperedhousing in the arm 2 to prevent excessive opening of the fixed andmovable jaws 1 a, 7 when locating the tool on the wire 13.

In use, the positioning foot 4 of the tool is placed against the fencepost 14 in the manner shown in FIG. 1. In this position the foot 4 ispivoted towards the fixed and moveable jaws. The jaws 1 a, 7 are intheir open position with further pivoting of the handle 3 prevented bythe pin 6. A fence wire 13, secured to a preceding post, is locatedbetween the jaws 1 a, 7 and leverage applied to the handle 3 pivots thehandle 3 about pin 5 causing the jaws 1 a, 7 to close, gripping the wire13. As soon as the wire 13 is locked in place by the pressure exertedbetween the jaws 1 a, 7, the force generated by leverage applied to thehandle 3 is transferred to the bolt 8 of the positioning foot 4. Thebolt 8 acts as a pivot and the action effects a class 2, lever actionbetween the post 14 and the handle 3, which in turn stretches the wire13.

Thus as the wire 13 is stretched the proportion of the bearing surface 4a in contact with the fence post 14 is constant. The bearing surface 4 ais formed by a pre-ribbed gripping section that is pressed into shapebefore welding. The presence of a gripping section on the bearingsurface 4 a coupled with the pressure exerted on the foot 4 towards thefence post 14 reduces the tendency of the foot 4 to slide around thepost 14 as the arm 2 pivots about the bolt 8. Still further, the wire 13is pulled advantageously towards the post 14 as the tool is leveredaround the bolt 8. The bearing surface radius of 75 mm is suitable formost diameters of fence post and is large enough for the maximum size offence post likely to be encountered.

The eccentric cam locking action of the jaw assembly 1 eliminatesslippage and consequential damage to the surface of the fence wire 13.Even in unfavourable conditions the configuration ensures that whateverpressure is being applied against the fence post 14 by the leverage ofthe handle 3, so a correspondingly greater pressure is applied betweenthe jaws 1 a, 7.

Once the tool has been employed, tension on the fence wire iseffectively maintained by a single handed movement on the handle 3 whilethe wire staple 15 is hammered into the post 14 in the usual manner. Theoperation is then repeated at each post along the fence.

The opposing sets of jaws 1 a, 7 allow for either left or right handedoperation of the tool from above or below the wire 13 and from eitherside of the fence line if working in restricted or difficult locations.

The distance between the two pivot points (i.e. from bolt 8 to pin 5) isabout 110 mm which may be varied depending on the dimensions of thewhole tool. The distance between the fixed jaw surfaces 7 and the pivotpoint of the positioning foot is about 85 mm (+−5 mm). The distancebetween the bearing surface 4 a and the pivot point of the positioningfoot 4 is suitable 40 mm (+−5 mm) taken along the line through thecentre of curvature of the bearing surface 4 a. The angle of the fixedjaw surface to the normal to the longitudinal axis of the arm 2 may varyby +−2.5°. It is important to the stability of the device that thedimensions chosen, especially for the bearing surface to pivot distanceand the pivot to jaw surface distance, result in the position of thejaws when the tool is located on a fence post being approximately inline with the line of the fence or wire suspended between the presentpost and the preceding post. The dimensions given above are for a toolsuitable for use up to a maximum post size of about 150 to 200 mm. Thefixed jaw angle allows the jaws to be lined up substantially with thelay of the wire so that the tool is in the correct position as it isoffered to the post. Only minimum movement of the handle is required tolock the wire in place before pressure on the handle is transferred tothe post via the foot.

Whilst an embodiment of the invention has been described with referenceto the accompanying drawings, modifications and variations will suggestthemselves to those skilled in the art without departing from the scopeof the invention as defined in the appended claims. The bolt 8 and pin 5may be replaced with any equivalent means such as rivets, or a pin orbolt as appropriate. The end of the handle or the arm member may includea hook (not shown) by which the tool can be conveniently hung on asuspended wire when the tool is not in use. The tool may be providedwith interchangeable positioning feet having different radius bearingsurfaces and/ or providing different distances between the bearingsurface and the pivot point. Furthermore, the intermediate arm membermay be adjustable so as to increase or decrease the pivot to jaw facedistance allowing adjustment for different post sizes.

Whilst in the embodiment described a movement limiting pin is used tolimit the rotational movement of the handle relative to the arm, the armcould sit in a cavity of the handle such that walls of the handleenclosing the arm prevent rotational movement beyond a certain limitedamount in either direction. It is sufficient for the handle to pivotsufficiently to open and close the jaws.

I claim:
 1. A fence wire tensioning tool comprising a handle (3)including a first jaw surface (1 a), the handle member being pivotallyattached to an intermediate arm member (2) carrying a second jaw surface(7) opposing said first jaw surface characterized in that said first andsecond jaw surfaces provide jaws for gripping a fence wire, and apivoting positioning foot (4) comprising a bearing surface (4 a) adaptedto abut against a fence post when said tool is pressed against saidfence post for engaging a fence post, the positioning foot (4) beingpivotally attached to said intermediate arm member (2) at a pivot point,whereby when the jaws (1 a, 7) are closed on a fence wire theintermediate arm member (2) and the handle (3) provide a lever pivotingabout the pivot point of the pivoting foot (4).
 2. A fence wiretensioning tool as claimed in claim 1, wherein said positioning foot (4)has a bearing surface with one of a serrated, ribbed, denticulate andfriction type material covered surface.
 3. A fence wire tensioning toolas claimed in claim 2, wherein leverage applied to the handle (3)effects a class 2 lever action between the pivot point of thepositioning foot and the jaws (1 a, 7).
 4. A fence wire tensioning toolas claimed in any claim 3, comprising a resilient means (11) associatedwith the handle (3) and acting against the leverage applied to thehandle.
 5. A fence wire tensioning tool as claimed in claim 2, whereinthe wire is gripped by said jaws (1 a, 7) which engage by means of aneccentric cam action.
 6. A fence wire tensioning tool as claimed inclaim 5, wherein said intermediate arm member and said handle membereach include a first and an opposite second side, said first and saidsecond jaw surfaces are located on said first side of said arm memberand said handle member respectively, and wherein said tool furthercomprises third and fourth jaw surfaces located on said second side ofsaid arm member and said handle member respectively, substantiallyopposite said first and said second jaw surfaces thereby allowing bothright and left handed operation of said tool.
 7. A fence wire tensioningtool as claimed in claim 6, comprising a resilient means (11) associatedwith the handle (3) and acting against the leverage applied to thehandle.
 8. A fence wire tensioning tool as claimed in claim 5,comprising a resilient means (11) associated with the handle (3) andacting against the leverage applied to the handle.
 9. A fence wiretensioning tool as claimed in claim 2, comprising a resilient means (11)associated with the handle (3) and acting against the leverage appliedto the handle.
 10. A fence wire tensioning tool as claimed in claim 1,wherein leverage applied to the handle (3) effects a double lever actionbetween the pivot point of the positioning foot and the jaws (1 a, 7).11. A fence wire tensioning tool as claimed in claim 10, wherein thewire is gripped by said jaws (1 a, 7) which engage by means of aneccentric cam action.
 12. A fence wire tensioning tool as claimed inclaim 11, wherein said intermediate arm member and said handle membereach include a first and an opposite second side, said first and saidsecond jaw surfaces are located on said first side of said arm memberand said handle member respectively, and wherein said tool furthercomprises third and fourth jaw surfaces located on said second side ofsaid arm member and said handle member respectively, substantiallyopposite said first and said second jaw surfaces thereby allowing bothright and left handed operation of said tool.
 13. A fence wiretensioning tool as claimed in claim 12, comprising a resilient means(11) associated with the handle (3) and acting against the leverageapplied to the handle.
 14. A fence wire tensioning tool as claimed inclaim 11, comprising a resilient means (11) associated with the handle(3) and acting against the leverage applied to the handle.
 15. A fencewire tensioning tool as claimed in claim 10, comprising a resilientmeans (11) associated with the handle (3) and acting against theleverage applied to the handle.
 16. A fence wire tensioning tool asclaimed in claim 1, wherein the wire is gripped by said jaws (1 a, 7)which engage by means of an eccentric cam action.
 17. A fence wiretensioning tool as claimed in claim 16, wherein said intermediate armmember and said handle member each include a first and an oppositesecond side, said first and said second jaw surfaces are located on saidfirst side of said arm member and said handle member respectively, andwherein said tool further comprises third and fourth jaw surfaceslocated on said second side of said arm member and said handle memberrespectively, substantially opposite said first and said second jawsurfaces thereby allowing both right and left handed operation of saidtool.
 18. A fence wire tensioning tool as claimed in claim 17,comprising a resilient means (11) associated with the handle (3) andacting against the leverage applied to the handle.
 19. A fence wiretensioning tool as claimed in claim 16, comprising a resilient means(11) associated with the handle (3) and acting against the leverageapplied to the handle.
 20. A fence wire tensioning tool as claimed inclaim 1, comprising a resilient means (11) associated with the handle(3) and acting against the leverage applied to the handle.
 21. A methodfor tensioning and attaching a fence wire to a fence post using a fencewire tensioning tool comprising a handle (3) a positioning foot (4) andan intermediate arm member (2) between said handle and said footpivotally connected to said handle and to said to said foot through ahandle pivot, and a foot pivot respectively, the handle including afirst jaw surface (1 a), the intermediate arm member (2) carrying asecond jaw surface (7) opposing said first jaw surface to provide jawsfor gripping a fence wire, the positioning foot (4) comprising a bearingsurface (4a) adapted to abut against a fence post when said tool ispressed against said fence post, wherein when the jaws (1 a, 7) areclosed on a wire the intermediate arm member (2) and the handle (3)provide a lever pivoting about the foot pivot point, the methodcomprising: abutting the bearing surface (4 a) of said foot (4) of thetool against said fence post and positioning said fence wire in saidjaws for gripping said fence wire; pivoting said handle about saidhandle pivot point to close said jaws and grip said wire in said jaws;continuing pivoting said handle to stretch said wire; and while holdingsaid handle pivoted and maintaining said wire stretched, attaching saidwire to said post.
 22. The method according to claim 21 wherein saidhandle is pivoted by an operator using one hand.
 23. The methodaccording to claim 22 wherein said operator uses another hand to attachsaid wire to said post with a wire staple.
 24. A fence wire tensioningtool comprising: (a) an elongated handle member, (b) a positioning footmember comprising a first pivot and an arcuate abutting surface spacedfrom said pivot, and (c) an intermediate member between said foot memberand said elongated handle; wherein said intermediate member is pivotallyconnected to said foot member through said first pivot and to saidelongated handle through a second pivot; and wherein said intermediatemember further comprises a first jaw surface and said elongated handlecomprises a second jaw surface, said second jaw surface located oppositesaid first jaw surface, said first and said second jaw surfacescooperating to grip a wire placed thereinbetween when said handle pivotsaround said second pivot.
 25. The wire tensioning tool according toclaim 24 further comprising a limiting pin to limit an arc through whichthe intermediate member swings around said second pivot relative to saidhandle.
 26. The wire tensioning tool according to claim 25 furthercomprising a spring cooperating with said intermediate arm and saidelongated handle to urge said intermediate arm relative to saidelongated handle to said limit of said arc defined by said limiting pin.